However, the universality of attraction of gravity may not be the case when one goes beyond the Einstein-Hilbert (EH) action, referred to as GR in literature. In order to demonstrate that, a quadratic deviation to the EH action is considered, which is a subclass of post-Einsteinian theories known as \( f\left(R\right) \)  theories of gravity [1]}, [2]}. Such theories are characterized by an extra massive scalar degree of freedom[3]}, [4]}, [5]}, in addition to the two massless tensor degrees of freedom.
